Worldwide, more than 10 million people are diagnosed with cancer every year and it is estimated that this number will grow to 15 million new cases every year by 2020. Cancer causes six million deaths every year or 12% of the deaths worldwide. There remains a need for methods that can treat cancer in a localized manner, thereby avoiding excessive toxicity or damage to non-cancerous tissues proximate to the cancerous tissue and to minimize the effects of systemic toxicity of agents by localizing the delivery of these agents. The present invention provides devices and methods to meet these needs.
Cancer can develop in any tissue of any organ at any age. The etiology of cancer is not clearly defined but mechanisms such as genetic susceptibility, chromosome breakage disorders, viruses, environmental factors and immunologic disorders have all been linked to a malignant cell growth and transformation. Cancer encompasses a large category of medical conditions, affecting millions of individuals worldwide. Cancer cells can arise in almost any organ and/or tissue of the body. Cancer develops when cells in a part of the body begin to grow or differentiate out of control. All cancer types begin with the out-of-control growth of abnormal cells.
There are many types of cancer, including, breast, lung, ovarian, bladder, prostate, pancreatic, cervical, and leukemia. Currently, some of the main treatments available are surgery, phototherapy, phytotherapy, cryosurgery, thermotherapy, radiation therapy, and chemotherapy.
Cryosurgery, or the destruction of undesired biological tissues by freezing, has long been accepted as an important alternative technique of surgery. Compared with conventional means of destroying tissues, such as surgical excision, radiotherapy and chemotherapy, visceral cryosurgery (especially minimal-invasive cryosurgery) offers the following potential advantages: simplicity of the procedure, minimal bleeding, anaesthetic effect of low temperatures, short period of patient recovery, low cost, minimal scarring, and possible stimulation of the body's immune system. Exemplary cryosurgery devices are described in Rabin et al., U.S. Pat. No. 5,899,897.
Thermotherapy treatment is a relatively new method of treating diseased and/or undesirably enlarged human tissues, e.g., prostate tissues. Hyperthermia treatment is well known in the art, involving the maintaining of a temperature between about 41.5° through 45° C. Thermotherapy, on the other hand, usually requires energy application to achieve a temperature above 45° C. for the purposes of coagulating the target tissue. Tissue coagulation beneficially changes the density of the tissue. As the tissue shrinks, forms scars and is reabsorbed, the impingement of the enlarged tissues, such as an abnormal prostate, is substantially lessened.
The higher temperatures required by thermotherapy require delivery of large amounts of energy to the target tissues. At the same time, it is important to shield nontarget tissues from the high thermotherapy temperatures used in the treatment. Providing safe and effective thermotherapy, therefore, requires devices which have further capability to direct heat to a desired region compared to those which are suitable for hyperthermia.
Phototherapy is a promising clinical tool for the treatment for many conditions, including, but not limited to, cancer. Exemplary phototherapy systems are described, e.g., in Kremenchugsky U.S. Pat. No. 5,339,223; Rosen U.S. Pat. No. 6,045,575; Russell U.S. Pat. No. 6,290,713; Larsson U.S. Pat. No. 5,792,214; Nicholas U.S. Pat. No. 5,400,425; Vreman U.S. Pat. No. 6,596,016; Williams U.S. Pat. No. 6,872,220; Williams U.S. Pub. No. 2004/0039428; Bansal U.S. Pub. No. 2004/0068305; and Gardner U.S. Pub. No. 2006/0100675.
Regardless of the technique used, it is important to limit the “leakage” of phototherapeutic light; that is, phototherapeutic light absorbed by non-cancerous tissue. Ideally, all the emitted light is absorbed by the locus of disease, however a significant percentage of the phototherapeutic light never strikes the locus of disease. Systems and devices are therefore needed focus the light during phototherapy.
Chemotherapy involves the administration of various anti-cancer drugs to a patient but due to the requirement that it be administered systemically, its use is accompanied by adverse side effects. Thus, devices and methods for delivering chemo-therapeutic agents to desired regions of disease are needed.
A fundamental goal for radiation oncology is precise delivery of radiation to tumors while sparing healthy tissue. It is critical to minimize the exposure of non-cancerous tissue to ionizing radiation during radiation therapy. Methods employing beams of photons or other sub-atomic or atomic particles generated outside the body and penetrating into the body and tumor location (external beam) can accumulate radiation at specific internal points, but radiation intensity is limited by the dose delivered to intervening non-cancerous tissue. In contrast, brachytherapy (a form of radiotherapy where needles are inserted into the body to place small radioactive sources near tumors) can place high-intensity radiation inside the body, circumventing the intervening non-cancerous tissue. Each year, over 500,000 cancer patients worldwide are treated with brachytherapy.
A problem with needles is that they are difficult to place precisely, their paths are limited to primarily linear forms, and that radiation is emitted uniformly in all directions when the seed is stationary. FIG. 10 displays representative conventional brachytherapy devices.
There remains a need for methods that can treat cancer and other diseases in a localized manner, thereby avoiding excessive toxicity or damage to non-cancerous tissues proximate to the cancerous tissue and, in the case of chemotherapy, to minimize the effects of systemic toxicity of chemotherapeutic agents by localizing the delivery of these agents. The present invention provides devices and methods to meet these needs.